1. Field of the Invention
The present invention relates to a rubber laminate for adhering onto a rubber article by vulcanization. More particularly, the present invention relates to a rubber laminate as a label for a rubber article.
2. Description of the Prior Arts
In the process of manufacturing a rubber tire, an unvulcanized raw tire is adhered with a label, and then subjected to vulcanization under heat or pressure to adhere the label on the raw tire and produce the rubber tire. With the heat or pressure, the conventional label printed with a desired image or symbol is usually detached from the rubber tire, and thus fails to keep its original image after the vulcanization.
With reference to U.S. Pat. No. 4,252,589, Hayakama et al. disclose that the thin rubber sheet provided with mark indications is partially vulcanized to a degree of vulcanization of 50-80%. If the degree of vulcanization is less than 50%, the thin rubber sheet softens and flows during the vulcanization, and thus the mark indication readily distorts after the vulcanization. The higher degree of vulcanization reduces the tack of the thin rubber sheet. If the degree of vulcanization is over 80%, the stuck rubber sheet does not concentrically deform and further the color patch does not adhere onto the outer layer rubber of the tire side wall when the tire is deformed into the toroidal shape. Both tack and peel strength between rubber sheet and green tire may not be sufficient to resist the inflation, causing the separation of the thin rubber sheet and green tire.
With reference to U.S. Pat. No. 5,413,652, Bohm et, al. disclose a method of applying a white side wall applique to a tire. Before vulcanization, a barrier layer in a range from 0.25 millimeters to 1.77 millimeters and a white decorative rubber layer in a range from 0.76 millimeters to 2.54 millimeters are laminated together. Since the laminate layer is either uncured or only partially cured and the barrier and white decorative rubber layers are too thick, the applique adhered onto the tire is also distorted after vulcanization.
To overcome the shortcomings, the present invention provides a rubber laminate to mitigate or obviate the aforementioned problems.